Ptarmigan and marmots

Posted: Sunday, August 30, 2009

By Mary Willson

We were strolling up the ridge, enjoying the last of the alpine flowers. Many species had already gone to seed, but a few species that are more characteristic of spring, such as moss campion, still sported a few blooms.

Occasional hawks drifted southward on the thermals, sometimes harassed by playful ravens. On an adjacent ridge we saw a large group of white dots, perhaps 30 or more mountain goats.

Across a small gully, we spotted a flock of ptarmigan, just too far away to be certain of the species, although we suspected they were willow ptarmigan.

Most of the flock appeared to be young ones, perhaps 12 or 14 good-sized chicks. They were very hard to count because they were so well camouflaged.

What appeared to be bits of rock or tundra would sometimes get up and move, only to disappear once more when they stopped moving.

Gradually, the flock moved up the draw - all but three young ones. These squatted together on a small rock outcrop, peeping piteously, as the others disappeared behind a boulder.

The main group foraged in the low vegetation, talking constantly to each other. A few took snow baths, digging down a little way into a nearby snowbank and tossing the snow over their backs.

The three separated chicks were certainly within earshot of the others, but they just sat and peeped, not even responding to some loud calls of the attending adults.

Finally, after many long minutes, an adult bird trotted back and stood tall, not far from the trio. One by one, they stood up. As the adult moved back toward the flock, one chick and then the other two slowly began to straggle after it. With lots of vocal encouragement, the three rejoined all the others, and the entire group moved slowly away.

That little saga was the big treat of the day. But we also enjoyed seeing numerous marmots, lazing about on rocks, standing lookout or gathering vegetation to take back to the burrow. Their season of hibernation is approaching all too swiftly.

These are hoary marmots, a species that inhabits high elevations down south. A study of North American marmot species some years ago found that lowland marmots (woodchucks) are generally monogamous, one male mating with one female. The yellow-bellied marmot of mid elevations is sometimes monogamous and sometimes polygynous (one male with two or more females).

The hoary marmot in the alpine zone Down South is apparently polygynous rather often, perhaps because suitable habitat is quite patchy, and females concentrate in the good areas.

Our marmots occur from sea level to mountaintops. I would love to know if polygyny in this species occurs here, and if it is more common at higher elevations.